[nautilus/wip/corey/fix-sort: 17/19] list-view: Keep track of the most recently sorted column

[António Fernandes <antoniof src gnome org>]

commit c72e6def48e47454d4b620f58c93753a8a1b6a3f
Author: Corey Berla <corey berla me>
Date:   Thu Oct 13 13:39:50 2022 -0700

    list-view: Keep track of the most recently sorted column
    
    In GtkColumnView, we don't know what column is being sorted on
    from clicking on the column headers.  This means that we can only
    save the sort order when the sort is intiated from the toolbar
    menu rather than the column headers.  As a workaround, keep
    track of the most recently used attribute used in the sorter.
    Then when ::changed is emmited on the sorter, update the metadata
    for what was used while sorting.  This is a pretty bad hack, but the
    current state is worse because
    1) The sort order is never saved in column view
    2) If the sort order was changed (i.e. in GridView), the user
    can't figure out why the order keeps reverting back to another state.

 src/nautilus-list-view.c | 112 +++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 98 insertions(+), 14 deletions(-)
---
diff --git a/src/nautilus-list-view.c b/src/nautilus-list-view.c
index a525cf438..4c5ab3eaf 100644
--- a/src/nautilus-list-view.c
+++ b/src/nautilus-list-view.c
@@ -44,6 +44,10 @@ struct _NautilusListView
     GtkColumnViewColumn *star_column;
     GtkWidget *column_editor;
     GHashTable *factory_to_column_map;
+
+    /* Column sort hack state */
+    gboolean column_header_was_clicked;
+    GQuark clicked_column_attribute_q;
 };
 
 G_DEFINE_TYPE (NautilusListView, nautilus_list_view, NAUTILUS_TYPE_LIST_BASE)
@@ -246,15 +250,34 @@ real_scroll_to_item (NautilusListBase *list_base_view,
     }
 }
 
+typedef struct
+{
+    GQuark attribute;
+    NautilusListView *view;
+} SortData;
+
 static gint
 nautilus_list_view_sort (gconstpointer a,
                          gconstpointer b,
                          gpointer      user_data)
 {
-    GQuark attribute_q = GPOINTER_TO_UINT (user_data);
+    SortData *data = user_data;
+    NautilusListView *self = data->view;
+    GQuark attribute_q = data->attribute;
     NautilusFile *file_a = nautilus_view_item_get_file (NAUTILUS_VIEW_ITEM ((gpointer) a));
     NautilusFile *file_b = nautilus_view_item_get_file (NAUTILUS_VIEW_ITEM ((gpointer) b));
 
+    /* Hack: We don't know what column is being sorted on when the column
+     * headers are clicked. So let's just look at what attribute was most
+     * recently used for sorting.
+     * https://gitlab.gnome.org/GNOME/gtk/-/issues/4833 */
+    if (self->clicked_column_attribute_q == 0 && self->column_header_was_clicked)
+    {
+        self->clicked_column_attribute_q = attribute_q;
+    }
+
+    g_return_val_if_fail (file_a != NULL && file_b != NULL, GTK_ORDERING_EQUAL);
+
     /* The reversed argument is FALSE because the columnview sorter handles that
      * itself and if we don't want to reverse the reverse. The directories_first
      * argument is also FALSE for the same reason: we don't want the columnview
@@ -672,12 +695,18 @@ action_sort_order_changed (GSimpleAction *action,
     model = nautilus_list_base_get_model (NAUTILUS_LIST_BASE (self));
     sorter = nautilus_view_model_get_sorter (model);
 
-    g_signal_handlers_block_by_func (sorter, on_sorter_changed, self);
-    /* FIXME: Set NULL to stop drawing the arrow on previous sort column
-     * to workaround https://gitlab.gnome.org/GNOME/gtk/-/issues/4696 */
-    gtk_column_view_sort_by_column (self->view_ui, NULL, FALSE);
-    gtk_column_view_sort_by_column (self->view_ui, sort_column, reversed);
-    g_signal_handlers_unblock_by_func (sorter, on_sorter_changed, self);
+    /* Ask the column view to sort by column if it hasn't just done so already. */
+    if (!self->column_header_was_clicked)
+    {
+        g_signal_handlers_block_by_func (sorter, on_sorter_changed, self);
+        /* FIXME: Set NULL to stop drawing the arrow on previous sort column
+         * to workaround https://gitlab.gnome.org/GNOME/gtk/-/issues/4696 */
+        gtk_column_view_sort_by_column (self->view_ui, NULL, FALSE);
+        gtk_column_view_sort_by_column (self->view_ui, sort_column, reversed);
+        g_signal_handlers_unblock_by_func (sorter, on_sorter_changed, self);
+    }
+
+    self->column_header_was_clicked = FALSE;
 
     set_directory_sort_metadata (nautilus_files_view_get_directory_as_file (NAUTILUS_FILES_VIEW (self)),
                                  target_name,
@@ -744,6 +773,7 @@ real_begin_loading (NautilusFilesView *files_view)
     NAUTILUS_FILES_VIEW_CLASS (nautilus_list_view_parent_class)->begin_loading (files_view);
 
     update_columns_settings_from_metadata_and_preferences (self);
+    self->clicked_column_attribute_q = 0;
 
     self->path_attribute_q = 0;
     g_clear_object (&self->file_path_base_location);
@@ -852,12 +882,60 @@ on_sorter_changed (GtkSorter       *sorter,
                    gpointer         user_data)
 {
     NautilusListView *self = NAUTILUS_LIST_VIEW (user_data);
+    NautilusViewModel *model = nautilus_list_base_get_model (NAUTILUS_LIST_BASE (self));
 
-    /* When user clicks a header to change sort order, we don't know what the
-     * new sort order is. Make sure the sort menu doesn't indicate a outdated
-     * action state. */
-    g_action_group_change_action_state (nautilus_files_view_get_action_group (NAUTILUS_FILES_VIEW (self)),
-                                        "sort", g_variant_new ("(sb)", "unknown", FALSE));
+    /* Set the conditions to capture the sort attribute the first time that
+     * nautilus_list_view_sort() is called. */
+    self->column_header_was_clicked = TRUE;
+    self->clicked_column_attribute_q = 0;
+
+    /* If there is only one file, enforce a comparison against a dummy item, to
+     * ensure nautilus_list_view_sort() gets called at least once. */
+    if (g_list_model_get_n_items (G_LIST_MODEL (model)) == 1)
+    {
+        NautilusViewItem *item = g_list_model_get_item (G_LIST_MODEL (model), 0);
+        g_autoptr (NautilusViewItem) dummy_item = NULL;
+
+        dummy_item = nautilus_view_item_new (nautilus_view_item_get_file (item),
+                                             NAUTILUS_LIST_ICON_SIZE_SMALL);
+
+        gtk_sorter_compare (sorter, item, dummy_item);
+    }
+}
+
+static void
+on_after_sorter_changed (GtkSorter       *sorter,
+                         GtkSorterChange  change,
+                         gpointer         user_data)
+{
+    NautilusListView *self = NAUTILUS_LIST_VIEW (user_data);
+    GActionGroup *action_group = nautilus_files_view_get_action_group (NAUTILUS_FILES_VIEW (self));
+    g_autoptr (GVariant) state = NULL;
+    const gchar *new_sort_text;
+    gboolean reversed;
+    g_autofree gchar *current_sort_text = NULL;
+
+    if (!self->column_header_was_clicked || self->clicked_column_attribute_q == 0)
+    {
+        return;
+    }
+
+    state = g_action_group_get_action_state (action_group, "sort");
+    g_variant_get (state, "(&sb)", &current_sort_text, &reversed);
+
+    new_sort_text = g_quark_to_string (self->clicked_column_attribute_q);
+
+    if (g_strcmp0 (new_sort_text, current_sort_text) == 0)
+    {
+        reversed = !reversed;
+    }
+    else
+    {
+        reversed = FALSE;
+    }
+
+    g_action_group_change_action_state (action_group, "sort",
+                                        g_variant_new ("(sb)", new_sort_text, reversed));
 }
 
 static guint
@@ -1025,6 +1103,7 @@ setup_view_columns (NautilusListView *self)
     for (GList *l = nautilus_columns; l != NULL; l = l->next)
     {
         NautilusColumn *nautilus_column = NAUTILUS_COLUMN (l->data);
+        SortData *data;
         g_autofree gchar *name = NULL;
         g_autofree gchar *label = NULL;
         GQuark attribute_q = 0;
@@ -1039,9 +1118,13 @@ setup_view_columns (NautilusListView *self)
                       "default-sort-order", &sort_order,
                       NULL);
 
+        data = g_new0 (SortData, 1);
+        data->attribute = attribute_q;
+        data->view = self;
+
         sorter = gtk_custom_sorter_new (nautilus_list_view_sort,
-                                        GUINT_TO_POINTER (attribute_q),
-                                        NULL);
+                                        data,
+                                        g_free);
 
         factory = gtk_signal_list_item_factory_new ();
         view_column = gtk_column_view_column_new (NULL, factory);
@@ -1115,6 +1198,7 @@ nautilus_list_view_init (NautilusListView *self)
     gtk_multi_sorter_append (sorter, g_object_ref (GTK_SORTER (directories_sorter)));
     gtk_multi_sorter_append (sorter, g_object_ref (gtk_column_view_get_sorter (self->view_ui)));
     g_signal_connect_object (sorter, "changed", G_CALLBACK (on_sorter_changed), self, 0);
+    g_signal_connect_object (sorter, "changed", G_CALLBACK (on_after_sorter_changed), self, G_CONNECT_AFTER);
 
     model = nautilus_list_base_get_model (NAUTILUS_LIST_BASE (self));
     nautilus_view_model_set_sorter (model, GTK_SORTER (sorter));